Air conditioning system for vehicle

ABSTRACT

An air conditioning system includes an air-cooling unit and an air-heating unit. On a first path in the cooling-unit, provided are a compressor for first refrigerant, a condenser for the first refrigerant, an expansion unit for the first refrigerant, and an evaporator to cool air. On a second path in the air-heating unit, provided are an air-conditioning radiator for second refrigerant, and a first valve for the second refrigerant (whether or not into the air-conditioning radiator) On a third path in the air-heating unit, provided are a driving-system heating element to heat third refrigerant, an internal heat exchanger to heat the third refrigerant, a heater core to heat air, a driving-system radiator for the third refrigerant, and a second valve for the third refrigerant (whether or not into the driving-system radiator). The air passing through the evaporator or the heater core is selectably sent into a vehicle compartment.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an air conditioning system for avehicle that can achieve air-heating and air-cooling.

2. Description of Related Art

A conventional air conditioning system is disclosed in Japanese PatentApplication Laid-Open Number 2002-98430. As shown in FIG. 18, the airconditioning system includes a heat-pump type cooling unit C and anair-heating circulation unit D. The heat-pump type cooling unit C has afirst circulation path 100 along which first refrigerant circulates. Theair-heating circulation unit D has a second circulation path 110 alongwhich second refrigerant (water) circulates and a third circulation path120 along which third refrigerant (water) circulates.

A compressor 101, a heat-radiating side of an internal heat exchanger102, an in-compartment heat exchanger 103, an expansion valve 104, anexternal heat exchanger 105 and an accumulator 109 are provided on thefirst circulation path 100 in the heat-pump type cooling unit C. Thein-compartment heat exchanger 103 is provided within an air-conditioningduct 106 opened toward a vehicle compartment. Variety of bypass paths100 a and 100 b and many of changeover valves 107 for changing overpaths of the first refrigerant are provided on the first circulationpath 100.

In a heating mode, each of the internal heat exchanger 102 and thein-compartment heat exchanger 103 functions as a condenser to radiateheat from the first refrigerant. In addition, the external heatexchanger 105 functions as an evaporator to receive heat by the firstrefrigerant. In a cooling mode, the external heat exchanger 105functions as a condenser to radiate heat from the first refrigerant. Inaddition, the in-compartment heat exchanger 103 functions as anevaporator to receive heat by the first refrigerant. The paths arechanged over to achieve the above functions in each mode.

A pump 111 for circulating the second refrigerant, a heater core 113, aheat-receiving side of the internal heat exchanger 102 and a fuel-cellstuck (heating element in a vehicle driving system) 122 are provided onthe second circulation path 110 in the air-heating circulation unit D.The heater core 113 is provided within the air-conditioning duct 106opened toward the vehicle compartment.

A pump 121 for circulating the third refrigerant, the fuel-cell stuck(heating element in a vehicle driving system) 122, a radiator 123, abypass path 124 for bypassing the radiator 123 and a changeover valve125 are provided on the third recirculation path 120 in the air-heatingcirculation unit D. The changeover valve 125 changes the flowing path ofthe third refrigerant to the radiator 123 or to the bypass path 124.

In the heating mode, the vehicle compartment is air-heated by heatsources, as which the in-compartment heat exchanger 103 in the heat-pumptype cooling unit C, the heater core 113 and the fuel-cell stuck 122function. In the cooling mode, the vehicle compartment is air-cooled bya cool source, as which the in-compartment heat exchanger 103 in theheat-pump type cooling unit C functions.

In the above conventional air-conditioning system, air-heating andair-cooling are achieved by using the heat-pump type cooling unit C andwaste heat from cooling water of the fuel-cell stuck 122. Therefore,heat source can be used effectively in a vehicle with little heat sourcein order to achieve fuel efficiency improvement, heating performanceimprovement under a very low temperature condition.

SUMMARY OF THE INVENTION

However, in the above conventional air-conditioning system, the bypasspaths 100 a and 100 b and the changeover valves 107 are needed in orderto change the flowing path of the first refrigerant in the heat-pumptype cooling unit C between the heating mode and the cooling mode. As aresult, structure of the heat-pump type cooling unit C must be complex.

Therefore, an object of the present invention is to provide an airconditioning system for a vehicle that achieves air-heating andair-cooling by using waste heat of a heat-pump type cooling unit andwaste heat from a heating element in a vehicle driving system and canachieve a simple structure of the heat-pump type cooling unit.

An aspect of the present invention is to provide an air conditioningsystem for a vehicle that includes a heat-pump type cooling unitincluding a first circulation path in which first refrigerant circulatesand an air-heating unit including a second circulation path in whichsecond refrigerant circulates and a third circulation path in which athird refrigerant circulates. Each of the second and third refrigerantsis liquid and capable of taking sensible heat change due toheat-changing. A compressor for compressing the first refrigerant, acondenser for radiating heat of the first refrigerant to the secondrefrigerant and also provided on the second circulation path, anexpansion unit for expanding the first refrigerant, and an evaporatorfor heat-exchanging between the first refrigerant expanded by theexpansion unit and air to cool the air are provided on the firstcirculation path. A first pump for circulating the second refrigerant,an air-conditioning radiator for radiating heat of the secondrefrigerant, and a first flow-path changeover unit for changing over thesecond refrigerant flowing to flow into the air-conditioning radiator orto bypass the air-conditioning radiator are provided on the secondcirculation path. A second pump for circulating the third refrigerant, adriving-system heating element for heat-exchanging with the thirdrefrigerant, an internal heat exchanger for heat-exchanging with thesecond refrigerant to heat the third refrigerant, a heater core forheat-exchanging between the third refrigerant and air to heat the air, adriving-system radiator for radiating heat of the third refrigerant, anda second flow-path changeover unit for changing over the thirdrefrigerant flowing to flow into the driving-system radiator or tobypass the driving-system radiator based on temperature of the thirdrefrigerant are provided on the third circulation path. The system isconfigured to send the air passing through the evaporator or the airpassing through the heater core into a vehicle compartment selectably.

According to the aspect of the present invention, during air-heating,the heat obtained at the condenser and from the driving-system heatingelement is radiated to the air passing through the heater core. Thisheated air is sent to the vehicle compartment. During air-cooling, thefirst refrigerant receives heat from the air passing through theevaporator. This cooled air passing through the evaporator is sent tothe vehicle compartment. Note that the waste heat of the heat-pump typecooling unit is discharged to the air outside the vehicle compartment atthe air-conditioning radiator. The waste heat of the driving-systemheating element is discharged to the air outside the vehicle compartmentat the driving-system radiator. Air-heating and air-cooling can beachieved in this manner. Here, the first refrigerant in the heat-pumptype cooling unit is circulated along the first circulation path (it isa fixed flowing path) regardless the operation modes (air-heating orair-cooling). Therefore, the heat-pump type cooling unit can besimplified in the air-conditioning system that achieves air-heating andair-cooling by using the waste heat of the heat-pump type cooling unitand the driving-system heating element.

It is preferable that the air-conditioning radiator and thedriving-system radiator are provided integrally.

According to this configuration, the air-conditioning radiator and thedriving-system radiator can be made down-sized and thereby their costscan be reduced.

It is preferable that the internal heat exchanger includes aheat-radiating section and a heat-receiving section, the heat-radiatingsection and the heat-receiving section are made coherent, and the secondrefrigerant flows through the heat-radiating section and the thirdrefrigerant flows through the heat-receiving section.

According to this configuration, heat-exchanging can be achieved in casewhere the second and third refrigerants are different.

It is preferable that the internal heat exchanger includes a heatexchanger through which at least one of the second and thirdrefrigerants flows and the heat exchanger is provided within a flowingpath through which another of the second and third refrigerants flows.

According to this configuration, it can be applied to the case where thesecond and third refrigerants are different. In addition, goodheat-exchange efficiency of the second and third refrigerants can beachieved.

It is preferable that the internal heat exchanger is arefrigerant-confluent unit into which the second and third refrigerantsflow together.

According to this configuration, configuration of the internal heatexchanger can be simplified and better heat-exchange efficiency can beachieved.

It is preferable that a third flow-path changeover unit for changingover the second refrigerant flowing to flow into the internal heatexchanger or to bypass the internal heat exchanger, is further providedon the second circulation path.

According to this configuration, heat-radiation from the heater coreduring the air-cooling operation can be prevented.

It is preferable that a fourth flow-path changeover unit for changingover whether or not to flow the third refrigerant to the internal heatexchanger and the heater core, is further provided on the thirdcirculation path.

According to this configuration, heat-radiation from the heater coreduring the air-cooling operation can be prevented without providing anybypass path.

It is preferable that the system is configured to make the thirdcirculation path into two circulation forms selectably. In one of thecirculation forms, the third refrigerant circulates along an integratedcirculation path integrally to flow through the driving-system heatingelement, the driving-system radiator, the heater core and the internalheat exchanger. In another of the circulation forms, the thirdrefrigerant circulates respectively along one divided circulation pathto flow through the driving-system heating element and thedriving-system radiator and another divided circulation path to flowthrough the heater core and the internal heat exchanger.

According to this configuration, the air-hating operation can take twooperation modes, a quick-heating mode with the integrated circulationpath and an engine warming-up/stable-heating mode with the dividedcirculation paths. In the quick-heating mode, the quick-heatingperformance can be improved because the heat of the heat-pump typecooling unit can be used for air-heating without heating thedriving-system heating element by using the integrated circulation path.In the engine warming-up/stable-heating mode, fuel efficiency and so onare improved because the waste heat of the driving-system heatingelement can be also used for air-heating by using the dividedcirculation paths.

It is preferable that a combined path is provided on the second andthird circulation paths and commonly belongs to the second and thirdcirculation paths, the heater core is provided on the combined path, andthe system is configured to make the third circulation path into twocirculation forms selectably. In one of the circulation forms, the thirdrefrigerant circulates along an integrated circulation path integrallyto flow through the driving-system heating element, the driving-systemradiator, the heater core and the internal heat exchanger. In another ofthe circulation forms, the third refrigerant circulates respectivelyalong one divided circulation path to flow through the driving-systemheating element and the driving-system radiator and another dividedcirculation path to flow through the heater core and the internal heatexchanger.

According to this configuration, configurations of the air-heatingcirculation unit can be simplified because some segment of the secondand third circulation paths is integrated and the integrated circulationpath or the divided circulation paths can be made selectably.

It is preferable that a heater is provided on at least one of the secondand third circulation paths.

According to this configuration, sufficient heating performance can beachieved under a very low temperature condition in a vehicle with littleheat source because heat from the heat-pump type cooling unit and theheater can be used for air-heating during the air-heating operation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a configuration diagram of an air conditioning systemaccording to a first embodiment of the present invention;

FIG. 2 is a configuration diagram showing refrigerant flows duringair-heating in the first embodiment;

FIG. 3 is a configuration diagram showing refrigerant flows duringair-cooling in the first embodiment;

FIG. 4 is a configuration diagram of an air conditioning systemaccording to a second embodiment of the present invention;

FIG. 5 is a configuration diagram showing refrigerant flows duringair-heating in the second embodiment;

FIG. 6 is a configuration diagram showing refrigerant flows duringair-cooling in the second embodiment;

FIG. 7 is a configuration diagram of an air conditioning systemaccording to a third embodiment of the present invention;

FIG. 8 is a configuration diagram showing refrigerant flows duringair-heating in the third embodiment;

FIG. 9 is a configuration diagram showing refrigerant flows duringair-cooling in the third embodiment;

FIG. 10 is a configuration diagram of an air conditioning systemaccording to a fourth embodiment of the present invention;

FIG. 11 is a configuration diagram showing refrigerant flows duringair-heating (quick-heating mode) in the fourth embodiment;

FIG. 12 is a configuration diagram showing refrigerant flows duringair-heating (engine warming-up/stable-heating mode) in the fourthembodiment;

FIG. 13 is a configuration diagram showing refrigerant flows duringair-cooling in the fourth embodiment;

FIG. 14 is a configuration diagram of an air conditioning systemaccording to a fifth embodiment of the present invention;

FIG. 15 is a configuration diagram showing refrigerant flows duringair-heating (quick-heating mode) in the fifth embodiment;

FIG. 16 is a configuration diagram showing refrigerant flows duringair-heating (engine warming-up/stable-heating mode) in the fifthembodiment;

FIG. 17 is a configuration diagram showing refrigerant flows duringair-cooling in the fifth embodiment; and

FIG. 18 is a configuration diagram of a conventional air conditioningsystem for a vehicle.

DETAILED DESCRIPTION OF THE EMBODIMENT

Hereinafter, embodiments according to the present invention will beexplained with reference to drawings.

A first embodiment of an air conditioning system for a vehicle accordingto the present invention will be explained with reference to FIGS. 1 to3. As shown in FIG. 1, the air conditioning system is combined of aheat-pump type cooling unit A and an air-heating circulation unit B1.

The heat-pump type cooling unit A includes a first circulation path 1.The first circulation path 1 is filled with first refrigerant (CO₂). Acompressor 2, a water-cooled condenser 3, an expansion valve (expansionunit) 4, an evaporator 5 and a accumulator 6 are provided on the firstcirculation path 1 in this order.

The compressor 2 inhales the relatively low-temperature and pressurefirst refrigerant and discharges the high-temperature and pressure firstrefrigerant after compressing it.

The water-cooled condenser 3 is arranged within an after-mentioned unitcontainer 14 on the second circulation path 10. The first refrigerantoutput from the compressor 2 is cooled by the second refrigerant.Specifically, heat-exchanging is achieved between the first refrigerantand the second refrigerant at the water-cooled condenser 3. The secondrefrigerant is heated by the first refrigerant.

The expansion valve 4 expands the first refrigerant (reduce the pressureof the first refrigerant) had passed through the water-cooled condenser3 and sends it to the evaporator 5 as a low-temperature and pressuregas.

The evaporator 5 achieves heat-exchanging between the first refrigerantliquid output from the expansion valve 4 and air passing through theevaporator 5. The air passing through the evaporator 5 is cooled down bythe first refrigerant. The evaporator 5 is provided within anair-conditioning duct (not shown). Cooled air passing through theevaporator 5 is send to an inside or an outside of a vehiclecompartment.

The accumulator 6 separates the first refrigerant output from theevaporator 5 into gas phase and liquid phase. The accumulator 6 sendsout the first refrigerant in the gas phase to the compressor 2 andtemporally holds the first refrigerant in the liquid phase therein.

The air-heating circulation unit B1 includes a second circulation path10. The second circulation path 10 is filled with second refrigerant(liquid such as water and antifreeze solution). A first pump 11, anair-conditioning radiator 12, a heat-radiating section 13 a of theinternal heat exchanger 13 and the unit container 14 are provided on thesecond circulation path 10 in this order. The unit container 14 is aspace having a larger cross-sectional area than that of the secondcirculation path 10. The above-mentioned water-cooled condenser 3 and anelectric heater 15 are contained within the unit container 13.

The first pump 11 inhales the second refrigerant and then pumps it outin order to circulates it along the second circulation path 10. Thesecond refrigerant liquid pumped by the first pump 11 circulates alongthe second circulation path 10 in liquid phase without changing itsphase. The second refrigerant takes sensible heat change due toheat-changing.

The air-conditioning radiator 12 is a unit for radiating heat of thesecond refrigerant to fresh air. The fresh air is blown to the radiator12 by an electric fan or air flow due to a vehicle running and thenheat-exchange is achieved between the second refrigerant and the freshair. The air-conditioning radiator 12 is provided integrally with anafter-mentioned radiator 23 in a vehicle driving system (driving-systemradiator 23).

The internal heat exchanger 13 includes the heat-radiating section 13 aand a heat-receiving section 13 b. The second refrigerant flows throughthe heat-radiating section 13 a and the third refrigerant flows throughthe heat-receiving section 13 b. The heat-radiating section 13 a and theheat-receiving section 13 b are made coherent each other. The thirdrefrigerant is heated by the second refrigerant within the internal heatexchanger 13.

The electric heater 15 is provided downstream of the water-cooledcondenser 3 and heats the second refrigerant by its heat with beingenergized.

A radiator-bypass path 16 is provided in the second circulation path 10so as to bypass the air-conditioning radiator 12. The second refrigerantflowing can be changed into the air-conditioning radiator 12 or theradiator-bypass path 16 by changing over a first flow-path changeovervalve (first flow-path changeover unit) 17 provided upstream of theradiator 12.

A heat-exchanger-bypass path 18 is provided in the second circulationpath 10 so as to bypass the heat-radiating section 13 a of the internalheat exchanger 13. The second refrigerant flowing can be changed intothe heat-radiating section 13 a or the heat-exchanger-bypass path 18 bychanging over a third flow-path changeover valve (third flow-pathchangeover unit) 19 provided upstream of the heat-radiating section 13a.

The air-heating circulation unit B1 includes a third circulation path20. The third circulation path 20 is filled with third refrigerant(liquid such as water, antifreeze solution or the like). A second pump21, an engine 22, the driving-system radiator 23, the heat-receivingsection 13 b of the internal heat exchanger 13 and a heater core 24 areprovided on the third circulation path 10. The engine 22 is an internalcombustion engine as a heating element in a vehicle driving system withlow water temperature.

The second pump 21 inhales the third refrigerant and then pumps it outin order to circulates it along the third circulation path 20. The thirdrefrigerant liquid pumped by the second pump 21 circulates along thethird circulation path 20 in liquid phase without changing its phase.The third refrigerant takes sensible heat change due to heat-changing.In the present embodiment, the same liquid is used as the second andthird refrigerants.

The engine 22 is driven with a low water temperature and used for anenvironmental protection vehicle due to its good engine efficiency. Theengine 22 is maintained with a desired temperature by heat-exchangingwith the third refrigerant.

The driving-system radiator 23 is a unit for radiating heat of the thirdrefrigerant to fresh air. The fresh air is blown to the driving-systemradiator 23 by an electric fan or air flow due to a vehicle running andthen heat-exchange is achieved between the third refrigerant and thefresh air.

The heater core 24 heats air passing through it by achievingheat-exchanging between the third refrigerant and the air passingthrough it. The heater core 24 is provided within the air-conditioningduct (not shown). The air passing thorough the heater core 24 can besent into a vehicle compartment.

A radiator-bypass path 25 is provided in the third circulation path 20so as to bypass the driving-system radiator 23. The third refrigerantflowing can be changed into the driving-system radiator 23 or theradiator-bypass path 25 by changing over a thermostat (second flow-pathchangeover unit) 26 provided downstream of the driving-system radiator23. Specifically, the thermostat 26 changes over the third refrigerantflowing according to temperature of the third refrigerant. When thetemperature of the third temperature is lower than a preset value, thethermostat 26 is changed over so as to flow the third refrigerantthrough the radiator-bypass path 25. When the temperature of the thirdtemperature is equal-to or higher-than the preset value, the thermostat26 is changed over so as to flow the third refrigerant through thedriving-system radiator 23. Therefore, the temperature of the thirdrefrigerant, in other words the temperature of the engine 22, iscontrolled within a predetermined temperature range.

Next, behavior of the above air conditioning system will be explained.

On an air-heating operation being selected as shown in FIG. 2, thecompressor 2 is driven in the heat-pump type cooling unit A. In theair-heating circulation unit B1, the first flow-path changeover valve 17is changed over so as to flow the second refrigerant through theradiator-bypass path 16 and the third flow-path changeover valve 19 ischanged over so as to flow the second refrigerant through the internalheat exchanger 13. The first pump 11 and the second pump 21 are driven.

In the heat-pump type cooling unit A, the first refrigerant radiates itsheat at the water-cooled condenser 3 and receive heat from air at theevaporator 5. The air passing through the evaporator 5 is dischargedoutside the vehicle compartment. In the water-cooled condenser 3, heatof the first refrigerant is radiated to the second refrigerant andthereby the second refrigerant is heated. Heat-exchanging between theheated second refrigerant and the third refrigerant is achieved at theinternal heat exchanger 13 and thereby the third refrigerant is heated.Heat of the third refrigerant is radiated to air at the heater core 24and thereby the air passing through the heater core 24 is heated. Theheated air is sent into the vehicle compartment for air-heating.

On driving the engine 22, heat of the engine 22 is radiated to the thirdrefrigerant. When the temperature of the third refrigerant reaches up tothe preset value, the heat of the engine is also used for air-heating.Namely, air-heating is achieved by the heat of the heat-pump typecooling unit A and the heat of the engine 22.

In addition, if the electric heater 15 is used, the air-heatingperformance is further improved due to heat generated by the electricheater 15. As a result, the air-heating performance can be givensufficiently even under a very low temperature condition.

On an air-cooling operation being selected as shown in FIG. 3, thecompressor 2 is driven in the heat-pump type cooling unit A. In theair-heating circulation unit B1, the first flow-path changeover valve 17is changed over so as to flow the second refrigerant through theair-conditioning radiator 12 and the third flow-path changeover valve 19is changed over so as to flow the second refrigerant through theheat-exchanger-bypass path 18. The first pump 11 and the second pump 21are driven.

In the heat-pump type cooling unit A, the first refrigerant radiates itsheat at the water-cooled condenser 3 and receive heat from air at theevaporator 5. The air passing through the evaporator 5 is cooled. Thecooled air is sent into the vehicle compartment for air-cooling.

In addition, heat of the first refrigerant is radiated to the secondrefrigerant in the water-cooled condenser 3 and thereby the secondrefrigerant is heated. Heat of the heated second refrigerant is radiatedat the air-conditioning radiator 12. Further, the thermostat 26 ischanged over so as to flow the third refrigerant through thedriving-system radiator 23 when the temperature of the engine 22 reachesup to the preset value. Superfluous heat (waste heat) of the engine 22is discharged at the driving-system radiator 23. In this manner, wasteheat of the heat-pump type cooling unit A and the engine is dischargedto air outside the vehicle compartment.

In the present embodiment as explained above, air-heating is achieved asfollows. The heat obtained at the water-cooled condenser 3 and from theengine 22 is radiated to the air passing through the heater core 24.This heated air is sent to the vehicle compartment. The cooled airpassing through the evaporator 5 is discharged outside the vehiclecompartment. On the other hand, air-cooling is achieved as follows. Thefirst refrigerant receives heat from the air passing through theevaporator 5. This cooled air passing through the evaporator 5 is sentto the vehicle compartment. The waste heat of the heat-pump type coolingunit A is discharged to the air outside the vehicle compartment at theair-conditioning radiator 12. The waste heat of the engine 22 isdischarged to the air outside the vehicle compartment at thedriving-system radiator 23. The first refrigerant in the heat-pump typecooling unit A is circulated along the first circulation path 1 (it is afixed flowing path) regardless the operation modes (air-heating orair-cooling). Therefore, the heat-pump type cooling unit A can besimplified in the air-conditioning system that achieves air-heating andair-cooling by using the waste heat of the heat-pump type cooling unit Aand the engine 22.

In the present embodiment, the air-conditioning radiator 12 and thedriving-system radiator 23 are provided integrally. Therefore, theair-conditioning radiator 12 and the driving-system radiator 23 can bemade down-sized and thereby their costs can be reduced. Since anidentical pressure-resistance specification can be applied to both theair-conditioning radiator 12 and the driving-system radiator 23, anidentical part(s) can be commonly used and thereby their costs can bereduced in this point due to their easily manufacturing.

In the present embodiment, the internal heat exchanger 13 is constructedby arranging the heat-radiating section 13 a, through which the secondrefrigerant flows, and the heat-receiving section 13 b, through whichthe third refrigerant flows, coherent each other. Although the secondand third refrigerants are the same in the present embodiment,heat-exchanging can be achieved in case where the second and thirdrefrigerants are different.

In the present embodiment, the third flow-path changeover valve 19 isprovided on the second circulation path 10 to change over the secondrefrigerant flowing to flow into the internal heat exchanger 13 or tobypass the internal heat exchanger 13. Therefore, heat-radiation fromthe heater core 24 during the air-cooling operation can be prevented.

Next, a second embodiment of an air conditioning system for a vehicleaccording to the present invention will be explained with reference toFIGS. 4 to 6. In the second embodiment as shown in FIG. 2, theheat-exchanger-bypass path 18 and the third flow-path changeover valve19 are not provided on the second circulation path 10 in a air-heatingcirculation unit B2 as compared with the first embodiment. Instead ofthem, a fourth flow-path changeover valve (fourth flow-path changeoverunit) 30 is provided just upstream of the heat-receiving section 13 b ofthe internal heat exchanger 13 on the third circulation path 20 in theair-heating circulation unit B2. The fourth flow-path changeover valve30 is used to close or open a flowing path of the third refrigerant.Specifically, the fourth flow-path changeover valve 30 changes overwhether or not to flow the third refrigerant to the heat-receivingsection 13 b and the heater core 24.

Since other configurations in the present embodiment are equal orsimilar to those in the above-described first embodiment, redundantexplanations will be omitted by allocating identical numerals to theidentical or similar configurations.

On an air-heating operation being selected as shown in FIG. 5, thefourth flow-path changeover valve 30 is changed over so as to flow thethird refrigerant through the heat-receiving section 13 b in theinternal heat exchanger 13 and the heater core 24. Other controls arethe same as those in the first embodiment. The air-heating in thevehicle compartment is achieved by the heat of the heat-pump typecooling unit A and the engine 22.

On an air-cooling operation being selected as shown in FIG. 6, thefourth flow-path changeover valve 30 is changed over so as not to flowthe third refrigerant through the heat-receiving section 13 b in theinternal heat exchanger 13 and the heater core 24. Other controls arethe same as those in the first embodiment. The air-heating in thevehicle compartment is achieved by the air passing through theevaporator 5. In addition, the waste heat of the heat-pump type coolingunit A and the engine 22 is discharged to air outside the vehiclecompartment.

In the present embodiment, the heat-pump type cooling unit A can besimplified in the air-conditioning system that achieves air-heating andair-cooling by using the waste heat of the heat-pump type cooling unit Aand the engine 22 as similarly as the first embodiment.

In the present embodiment, the fourth flow-path changeover valve 30 isprovided to change over whether or not to flow the third refrigerant tothe internal heat exchanger 13 and the heater core 24. Therefore, it isunnecessary to provide the heat-exchanger-bypass path 18 as in the firstembodiment and thereby heat-radiation from the heater core 24 during theair-cooling operation can be prevented.

Next, a third embodiment of an air conditioning system for a vehicleaccording to the present invention will be explained with reference toFIGS. 7 to 9. In the third embodiment as shown in FIG. 7, an internalheat exchanger 13A in an air-heating circulation unit B3 is different ascompared with the second embodiment.

The internal heat exchanger 13A includes a heat exchanger 13 c throughwhich the third refrigerant flows. The heat exchanger 13 c is providedwithin the unit container 14 inside which the second refrigerant flows.In other words, the water-cooled condenser 3 and the heat exchanger 13 care provided within the unit container 14 on the second circulation path10.

Since other configurations in the present embodiment is equal or similarto those in the second embodiment, redundant explanations will beomitted by allocating identical numerals to the identical or similarconfigurations.

As shown in FIG. 8, operations during air-heating are almost the same asthe second embodiment. As shown in FIG. 9, operations during air-coolingare almost the same as the second embodiment.

In the present embodiment, the heat-pump type cooling unit A can besimplified in the air-conditioning system that achieves air-heating andair-cooling by using the waste heat of the heat-pump type cooling unit Aand the engine 22 as similarly as the second embodiment.

In the present embodiment, the internal heat exchanger 13A includes theheat exchanger 13 c through which the third refrigerant flows and theheat exchanger 13 c is provided on (within) the flowing path of thesecond refrigerant, more specifically within the unit container 14.Therefore, this configuration can be applied to the case where thesecond and third refrigerants are different. In addition, heat-exchangeefficiency is better than the first and second embodiments.

On the contrary, it may be possible that the internal heat exchanger 13Aincludes a heat exchanger through which the second refrigerant flows andthe heat exchanger is provided on (within) the flowing path of the thirdrefrigerant.

Next, a fourth embodiment of an air conditioning system for a vehicleaccording to the present invention will be explained with reference toFIGS. 10 to 13. In the fourth embodiment as shown in FIG. 10, the thirdcirculation path 20 on an air-heating circulation unit B4 is differentas compared with the third embodiment.

Specifically, a branching path 31, a fifth flow-path changeover valve(fifth flow-path changeover unit) 32 and a third pump 33 are furtherprovided on the third circulation path 20. The branching path 31 dividesthe third circulation path 20 into a circulation system of the engine 22and another circulation system of the heater core 24. The fifthflow-path changeover valve 32 changes over whether or not to flow thethird refrigerant to the branching path 31. The third pump 33 isprovided for the branching path 31. The branching path 31 is interposedbetween the fourth flow-path changeover valve 30 and the fifth flow-pathchangeover valve 32. It can be controlled by changing over the fourthflow-path changeover valve 30 and the fifth flow-path changeover valve32 whether or not to flow the third refrigerant to the branching path31. Although the fourth flow-path changeover valve 30 is used to closeor open the flowing path in the above third embodiment, it is used tochange over or close the flowing path.

According to the above configurations, the third refrigerant can beselectably flown in two modes. In an engine warming-up/stable-heatingmode, the third refrigerant circulates along an integrated circulationpath c (see FIG. 12) to flow integrally through both a side with theengine 22 and the driving-system radiator 23 and another side with theheater core 24 and the internal heat exchanger 13A. In a quick-heatingmode, the third refrigerant circulates along divided circulation paths aand b (see FIG. 11) to flow independently each of the side with theengine 22 and the driving-system radiator 23 (divided path b) and theother side with the heater core 24 and the internal heat exchanger 13A(divided path a).

Since other configurations in the present embodiment is equal or similarto those in the third embodiment, redundant explanations will be omittedby allocating identical numerals to the identical or similarconfigurations.

On the quick-heating mode of an air-heating operation being selected asshown in FIG. 11, the compressor 2 is driven in the heat-pump typecooling unit A. In the air-heating circulation unit B4, the firstflow-path changeover valve 17 is changed over so as to flow the secondrefrigerant through the radiator-bypass path 16. The fourth flow-pathchangeover valve 30 and the fifth flow-path changeover valve 32 arechanged over so as not to flow the third refrigerant flowing from theengine 22 to the internal heat exchanger 13A and the heater core 24 andso as to flow the third refrigerant flowing from the internal heatexchanger 13A and the heater core 24 to the branching path 31. The firstto third pumps 11, 21 and 33 are driven.

As shown by arrows shown in FIG. 11, the two divided paths a and b aremade in the third circulation path 20. Therefore, the third refrigerantheated at the water-cooled condenser 3 radiates only at the heater core24. The air passing through the heater core 24 is sent into the vehiclecompartment for air-heating. Namely, the heat of the third refrigerantis not radiated to the engine 22 as in the first to third embodimentsand thereby the quick-heating performance can be improved.

On the engine warming-up/stable-heating mode of the air-heatingoperation being selected as shown in FIG. 12, the fourth flow-pathchangeover valve 30 and the fifth flow-path changeover valve 32 arechanged over so as not to flow the third refrigerant to the branchingpath 31. The first to third pumps 11, 21 and 33 are driven.

As shown by arrows shown in FIG. 12, the integrated circulation path cis made in the third circulation path 20. Therefore, the thirdrefrigerant heated at the water-cooled condenser 3 radiates at theheater core 24 and at the engine 22 until the engine 22 is warmed up toa prescribed temperature value. Therefore, fuel efficiency improvementcan be achieved through friction reduction and shortening warming-uptime with respect to the engine 22.

On an air-cooling operation being selected as shown in FIG. 13, thecompressor 2 is driven in the heat-pump type cooling unit A. In theair-heating circulation unit B4, the first flow-path changeover valve 17is changed over so as to flow the second refrigerant through theair-conditioning radiator 12. In addition, the fourth flow-pathchangeover valve 30 is changed over so as not to flow the thirdrefrigerant through the heat-receiving section 13 c in the internal heatexchanger 13A and the heater core 24. Further, the fifth flow-pathchangeover valve 32 is changed over so as not to flow the thirdrefrigerant through the branching path 31. The first pump 11 and thesecond pump 21 are driven.

Next, a fifth embodiment of an air conditioning system for a vehicleaccording to the present invention will be explained with reference toFIGS. 14 to 17. In the fifth embodiment as shown in FIG. 14, the secondcirculation path 10 and the third circulation path 20 on an air-heatingcirculation unit B5 is different as compared with the third embodiment.

Specifically, some segment of the second circulation path 10 and thethird circulation path 20 is provided as a combined path 40 for each ofthe paths 10 and 20. A unit container 14B and the heater core 24 areprovided on the combined path 40. The unit container 14B is arefrigerant-confluent unit, into which the second refrigerant in thesecond circulation path 10 and the third refrigerant in the thirdcirculation path 20 flow together. Within the refrigerant-confluentunit, heat-exchanging between the both refrigerants is achieved. Namely,the unit container (refrigerant-confluent unit) 14B constitutes aninternal heat exchanger 13B. Consequently, an identical refrigerant isused as the second and third refrigerants in the present embodiment.Therefore, the refrigerant flowing along the second circulation path 10and the third circulation path 20 may be merely referred as the“refrigerant”, hereinafter.

In addition, the heater core 24 is provided on the combined path 40.Further, a sixth flow-path changeover valve (sixth flow-path changeoverunit) 41 is provided at a branch point from the combined path 40 to thesecond and third circulation paths 10 and 20. The sixth flow-pathchangeover valve 41 changes over the refrigerant flowing to the secondcirculation path 20 or to the third circulation path 20.

Furthermore, any air-conditioning bypass path (such as theradiator-bypass path 16 and the heat-exchanger-bypass path 18) and thefirst flow-path changeover valve 17 are not provided.

In the quick-heating mode of the air-heating operation as shown in FIG.15, the divided circulation paths a and b of the third refrigerant canbe made in the third circulation path 20. In the an enginewarming-up/stable-heating mode as shown in FIG. 16, the integratedcirculation path c of the third refrigerant can be made in the thirdcirculation path 20. On the air-cooling operation being selected asshown in FIG. 17, the waste heat of the water-cooled heat exchanger 3can be discharged to the air outside the vehicle compartment at theair-conditioning radiator 12 and the waste heat of the engine 22 can bedischarged to the air outside the vehicle compartment at thedriving-system radiator 23. Note that, since the refrigerant flowsthrough the heater core 24 during the air-cooling operation in thepresent embodiment, the heated air passing through the heater core 24can be sent selectably into the vehicle compartment or outside thevehicle compartment. In addition, heat-radiation from the heater corecan be prevented by blocking air-flow to the heater core 24 using amixture door or the like.

Further, some segment of the second circulation path 10 and the thirdcirculation path 20 is integrated as the combined path 40 in the presentembodiment. Furthermore, since the divided circulation paths a and b orthe integrated circulation path c can be made, configurations of theair-heating circulation unit B5 can be simplified.

In the first to fifth embodiments, plural pumps are provided (the firstand second pumps 11 and 21 in the first embodiment, the first to thirdpumps 11, 21, and 33 in the fourth embodiment, the first and third pumps11 and 33 in the fifth embodiment). However, only a single pump may beprovided so as to drive plural liquid pumping unit by the single pump.In this manner, cost for the pump(s) can be reduced and configurationsof the air-heating circulation unit B1 to B5 can be simplified.

In the first to fifth embodiments, the driving-system heating element(heating element in a vehicle driving system) is the engine 22 with lowwater temperature. However, the driving-system heating element may be afuel-cell stuck or the like.

1. An air conditioning system for a vehicle, comprising a heat-pump typecooling unit including a first circulation path in which firstrefrigerant circulates and an air-heating unit including a secondcirculation path in which second refrigerant circulates and a thirdcirculation path in which a third refrigerant circulates; each of thesecond and third refrigerants being liquid and capable of takingsensible heat change due to heat-changing, wherein, on the firstcirculation path, provided are a compressor for compressing the firstrefrigerant, a condenser for radiating heat of the first refrigerant tothe second refrigerant and also provided on the second circulation path,an expansion unit for expanding the first refrigerant, and an evaporatorfor heat-exchanging between the first refrigerant expanded by theexpansion unit and air to cool the air; on the second circulation path,provided are a first pump for circulating the second refrigerant, anair-conditioning radiator for radiating heat of the second refrigerant,and a first flow-path changeover unit for changing over the secondrefrigerant flowing to flow into the air-conditioning radiator or tobypass the air-conditioning radiator; on the third circulation path,provided are a second pump for circulating the third refrigerant, adriving-system heating element for heat-exchanging with the thirdrefrigerant, an internal heat exchanger for heat-exchanging with thesecond refrigerant to heat the third refrigerant, a heater core forheat-exchanging between the third refrigerant and air to heat the air, adriving-system radiator for radiating heat of the third refrigerant, anda second flow-path changeover unit for changing over the thirdrefrigerant flowing to flow into the driving-system radiator or tobypass the driving-system radiator based on temperature of the thirdrefrigerant; and the system is configured to send the air passingthrough the evaporator or the air passing through the heater core into avehicle compartment selectably.
 2. The air conditioning system accordingto claim 1, wherein, the air-conditioning radiator and thedriving-system radiator are provided integrally.
 3. The air conditioningsystem according to claim 1, wherein, the internal heat exchangerincludes a heat-radiating section and a heat-receiving section, theheat-radiating section and the heat-receiving section are made coherent,and the second refrigerant flows through the heat-radiating section andthe third refrigerant flows through the heat-receiving section.
 4. Theair conditioning system according to claim 1, wherein, the internal heatexchanger includes a heat exchanger through which at least one of thesecond and third refrigerants flows and the heat exchanger is providedwithin a flowing path through which another of the second and thirdrefrigerants flows.
 5. The air conditioning system according to claim 1,wherein, the internal heat exchanger is a refrigerant-confluent unitinto which the second and third refrigerants flow together.
 6. The airconditioning system according to claim 1, wherein, a third flow-pathchangeover unit for changing over the second refrigerant flowing to flowinto the internal heat exchanger or to bypass the internal heatexchanger, is further provided on the second circulation path.
 7. Theair conditioning system according to claim 1, wherein, a fourthflow-path changeover unit for changing over whether or not to flow thethird refrigerant to the internal heat exchanger and the heater core, isfurther provided on the third circulation path.
 8. The air conditioningsystem according to claim 1, wherein, the system is configured to makethe third circulation path into two circulation forms selectably, in oneof the circulation forms, the third refrigerant circulates along anintegrated circulation path integrally to flow through thedriving-system heating element, the driving-system radiator, the heatercore and the internal heat exchanger, and in another of the circulationforms, the third refrigerant circulates respectively along one dividedcirculation path to flow through the driving-system heating element andthe driving-system radiator and another divided circulation path to flowthrough the heater core and the internal heat exchanger.
 9. The airconditioning system according to claim 1, wherein, a combined path isprovided on the second and third circulation paths and commonly belongsto the second and third circulation paths, the heater core is providedon the combined path, the system is configured to make the thirdcirculation path into two circulation forms selectably, in one of thecirculation forms, the third refrigerant circulates along an integratedcirculation path integrally to flow through the driving-system heatingelement, the driving-system radiator, the heater core and the internalheat exchanger, and in another of the circulation forms, the thirdrefrigerant circulates respectively along one divided circulation pathto flow through the driving-system heating element and thedriving-system radiator and another divided circulation path to flowthrough the heater core and the internal heat exchanger.
 10. The airconditioning system according to claim 1, wherein, a heater is providedon at least one of the second and third circulation paths.